我国中部地区典型人工水库多环芳烃空间分布特征、来源解析与风险评价

Distribution characteristics,source diagnosis and risk assessment of polycyclic aromatic hydrocarbons in a typical artificial reservoir in central China

我国中部地区的典型人工水库——漳河水库,是重要的饮用水源地。近年来,随着当地工业化和城市化的发展,尤其是煤矿的开采,多环芳烃(PAHs)的污染可能威胁到饮用水安全。为评估水库中PAHs的污染现状,测定了水体和沉积物中16种优控PAHs的含量,探究了其组成与空间分布特征,解析了其来源,并评估了其生态风险和健康风险。结果表明:水体和沉积物中∑_(16)PAHs的含量(均值±标准差)分别为69.6~509.0 ng/L[(142±89.4)ng/L]和15.9~399.0 ng/g[(205±104)ng/g];水体中以2~3环低分子量PAHs为主,沉积物中以4~6环中高分子量PAHs为主;采用特征比值法和主成分分析-多元线性回归(PCA-MLR)法对PAHs来源进行解析,结果表明低温燃烧源与石油源的混合污染源是漳河水库水体PAHs的主要来源,而沉积物则受到交通排放源与煤炭及生物质燃烧混合污染源的共同影响,这可能与水库周边存在的废弃煤矿以及铁路机场等交通设施有关;漳河水库沉积物中PAHs的潜在生态风险评价结果表明漳河水库除东侧2个点位外,其他点位均不存在PAHs的潜在生态风险;漳河水库水体中PAHs的终生致癌风险(∑ILCRs)结果介于10^(-6)~10^(-4)之间,表明风险水平在可接受范围内。

Zhanghe Reservoir,a typical artificial reservoir in central China,is an important drinking water source.In recent years,with the development of industrialization and urbanization,especially the mining of local coal mines,polycyclic aromatic hydrocarbons(PAHs)pollution may pose a threat to drinking water quality.In this research,we determined the concentrations of 16 priority PAHs in the water and sediment of reservoir and analyzed the composition characteristics,spatial distribution,source diagnosis and risk assessment of PAHs.The results show that the concentrations(average)of∑_(16)PAHs in water and sediment are 69.6~509 ng/L[(142±89.4)ng/L],and 5.90~399 ng/g[(205±104)ng/g],respectively.Human activities influence the spatial distribution of PAHs concentration,which is higher at sites closer to the reservoir shore.The PAHs in water are mainly composed of 2~3 rings,while the PAHs in sediment are mainly made up of 4~6 rings.We used characteristic ratio method and principal component analysis-multi-linear regression(PCAMLR)method to analyze the source of PAHs.The results show that the low-temperature combustion source and oil source are the main source of PAHs in the reservoir water,and the sediment is affected by common influence of the traffic emission source and coal and biomass burning source.Potential ecological risks indicate that there is no potential ecological risk of PAHs,except at 2 sites at the east side of the reservoir.And lifelong carcinogenic risk(ILCR)results range from 10^(-6)≤ΣILCRs≤10^(-4) within acceptable ranges.